From: Luca Ceresoli <luca@lucaceresoli.net>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>,
linux-i2c@vger.kernel.org
Cc: "Jacopo Mondi" <jacopo@jmondi.org>,
linux-kernel@vger.kernel.org, "Vladimir Zapolskiy" <vz@mleia.com>,
linux-renesas-soc@vger.kernel.org,
"Kieran Bingham" <kieran@bingham.xyz>,
"Laurent Pinchart" <laurent.pinchart@ideasonboard.com>,
"Niklas Söderlund" <niklas.soderlund@ragnatech.se>,
linux-i3c@lists.infradead.org
Subject: Re: [RFC PATCH v2 6/6] i2c: core: hand over reserved devices when requesting ancillary addresses
Date: Wed, 15 Apr 2020 12:07:24 +0200 [thread overview]
Message-ID: <610bbd01-e245-3320-c315-7a5c945a700d@lucaceresoli.net> (raw)
In-Reply-To: <20200318150059.21714-7-wsa+renesas@sang-engineering.com>
Hi,
On 18/03/20 16:00, Wolfram Sang wrote:
> With i2c_new_ancillary_address, we can check if the intended driver is
> requesting a reserved address. Update the function to do these checks.
> If the check passes, the "reserved" device will become a regular "dummy"
> device.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
> drivers/i2c/i2c-core-base.c | 24 ++++++++++++++++++++++--
> 1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 84464e439df5..81fb320de28d 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -974,7 +974,9 @@ struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
> const char *name,
> u16 default_addr)
> {
> - struct device_node *np = client->dev.of_node;
> + struct device_node *reserved_np, *np = client->dev.of_node;
> + struct device *reserved_dev, *adapter_dev = &client->adapter->dev;
> + struct i2c_client *reserved_client = NULL;
> u32 addr = default_addr;
> int i;
>
> @@ -984,7 +986,25 @@ struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
> of_property_read_u32_index(np, "reg", i, &addr);
> }
>
> - dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
> + dev_info(adapter_dev, "Address for %s : 0x%x\n", name, addr);
Here if we have two identical chips on the same bus, they probably will
both add an ancillary device with the same name. Then a message like:
i2c i2c-0: ds90ub954-q1: Address for rxport0: 0x40
won't tell which ds90ub954-q1 device is using that address. I'd rather
disambiguate using something like:
dev_info(adapter_dev, "%s: Address for %s: 0x%x\n",
dev_name(&client->dev), name, addr);
Sure, this issue did exist before this patch, but since the line is
being promoted from dbg to info (which is OK), it's probably a good idea
to improve the content, perhaps in a separate patch.
Except for that, I tested the patch and it's working fine.
--
Luca
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next prev parent reply other threads:[~2020-04-15 10:07 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-18 15:00 [RFC PATCH v2 0/6] i2c: of: reserve unknown and ancillary addresses Wolfram Sang
2020-03-18 15:00 ` [RFC PATCH v2 1/6] i2c: use DEFINE for the dummy driver name Wolfram Sang
2020-04-15 8:09 ` Kieran Bingham
2020-03-18 15:00 ` [RFC PATCH v2 2/6] i2c: allow DT nodes without 'compatible' Wolfram Sang
2020-04-10 13:49 ` Luca Ceresoli
2020-04-15 7:59 ` Wolfram Sang
2020-04-15 8:07 ` Kieran Bingham
2020-04-15 8:16 ` Wolfram Sang
2020-04-15 8:38 ` Kieran Bingham
2020-04-16 14:53 ` Luca Ceresoli
2020-04-15 8:48 ` Kieran Bingham
2020-04-15 9:46 ` Wolfram Sang
2020-03-18 15:00 ` [RFC PATCH v2 3/6] i2c: of: remove superfluous parameter from exported function Wolfram Sang
2020-03-19 12:41 ` Boris Brezillon
2020-04-15 8:13 ` Kieran Bingham
2020-03-18 15:00 ` [RFC PATCH v2 4/6] i2c: of: error message unification Wolfram Sang
2020-04-10 17:02 ` Luca Ceresoli
2020-04-15 8:17 ` Kieran Bingham
2020-04-15 8:50 ` Kieran Bingham
2020-03-18 15:00 ` [RFC PATCH v2 5/6] i2c: of: mark a whole array of regs as reserved Wolfram Sang
2020-04-10 17:05 ` Luca Ceresoli
2020-04-13 9:55 ` Luca Ceresoli
2020-04-15 8:10 ` Wolfram Sang
2020-04-15 10:07 ` Luca Ceresoli
2020-03-18 15:00 ` [RFC PATCH v2 6/6] i2c: core: hand over reserved devices when requesting ancillary addresses Wolfram Sang
2020-04-15 10:07 ` Luca Ceresoli [this message]
2020-03-28 3:50 ` [RFC PATCH v2 0/6] i2c: of: reserve unknown and " Wolfram Sang
2020-04-15 8:27 ` Wolfram Sang
2020-04-15 8:35 ` Kieran Bingham
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